Mitch - The unofficial mobile app for itch.io
LaunchBox - LaunchBox is a portable, box-art-based games database and launcher for DOSBox, emulators, arcade cabinets, and PC Games. Download it free!
GameDatum.com - A platfrom of free online games. A list of all the available online free games from various producers online.
GameEx - GameEx is considered to be the most powerful and feature rich front-end for MAME, GameBase, Daphne, PC Games and all command line based game emulators, along with being a complete Home Theatre PC solution.
ScienceGameCenter - The goal of the Science Game Center is to demonstrate to teachers, scientists, museums, and parents the myriad ways games can be used to improve education in math and science.
GamersGate - Buy and download games instantly for PC and Mac.